In the automotive industry, remote keyless entry ("RKE") systems have become standard equipment on many new vehicles. Comprising a receiver within the car and a number of fob transmitters for transmitting a message to the receiver, RKE systems enable users to control several vehicle functions remotely, such as the door locks and trunk, for example.
In providing remote control to vehicle functions, a problem arises as to restricting remote access to the automobile's owners and other authorized users. To prevent unauthorized access, an identification system is incorporated with a security code or codes within both the fob transmitter and receiver. The receiver receives a transmitted signal having a command and and identification or security code and compares the received code with the security code stored in its memory. If the receiver determines the received security code to match the stored code, the command is initiated for. execution.
As the demand for RKE systems has evolved in the marketplace, greater emphasis has been placed on increased security, reliability and flexibility. With the development of sophisticated electronics, presently, a transmitted message may be decoded and retransmitted at a later time. This is in part because in these known systems the transmitted message, does not change between transmissions.
As such, one area of focus has been the incorporation of encryption techniques to decrease the likelihood of unauthorized reception and retransmission of the originally transmitted signal comprising both the command and security code. Therefore, there is a demand for an encryption method designed specifically for RKE systems. Moreover, a need further exists for a RKE system which encrypts the transmitted message.